// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2016 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include "main.h"
#include <Eigen/Cholesky>
#include <Eigen/LU>
#include <Eigen/QR>

// This file test inplace decomposition through Ref<>, as supported by Cholesky, LU, and QR decompositions.

template<typename DecType, typename MatrixType>
void
inplace(bool square = false, bool SPD = false)
{
	typedef typename MatrixType::Scalar Scalar;
	typedef Matrix<Scalar, MatrixType::RowsAtCompileTime, 1> RhsType;
	typedef Matrix<Scalar, MatrixType::ColsAtCompileTime, 1> ResType;

	Index rows = MatrixType::RowsAtCompileTime == Dynamic ? internal::random<Index>(2, EIGEN_TEST_MAX_SIZE / 2)
														  : Index(MatrixType::RowsAtCompileTime);
	Index cols = MatrixType::ColsAtCompileTime == Dynamic ? (square ? rows : internal::random<Index>(2, rows))
														  : Index(MatrixType::ColsAtCompileTime);

	MatrixType A = MatrixType::Random(rows, cols);
	RhsType b = RhsType::Random(rows);
	ResType x(cols);

	if (SPD) {
		assert(square);
		A.topRows(cols) = A.topRows(cols).adjoint() * A.topRows(cols);
		A.diagonal().array() += 1e-3;
	}

	MatrixType A0 = A;
	MatrixType A1 = A;

	DecType dec(A);

	// Check that the content of A has been modified
	VERIFY_IS_NOT_APPROX(A, A0);

	// Check that the decomposition is correct:
	if (rows == cols) {
		VERIFY_IS_APPROX(A0 * (x = dec.solve(b)), b);
	} else {
		VERIFY_IS_APPROX(A0.transpose() * A0 * (x = dec.solve(b)), A0.transpose() * b);
	}

	// Check that modifying A breaks the current dec:
	A.setRandom();
	if (rows == cols) {
		VERIFY_IS_NOT_APPROX(A0 * (x = dec.solve(b)), b);
	} else {
		VERIFY_IS_NOT_APPROX(A0.transpose() * A0 * (x = dec.solve(b)), A0.transpose() * b);
	}

	// Check that calling compute(A1) does not modify A1:
	A = A0;
	dec.compute(A1);
	VERIFY_IS_EQUAL(A0, A1);
	VERIFY_IS_NOT_APPROX(A, A0);
	if (rows == cols) {
		VERIFY_IS_APPROX(A0 * (x = dec.solve(b)), b);
	} else {
		VERIFY_IS_APPROX(A0.transpose() * A0 * (x = dec.solve(b)), A0.transpose() * b);
	}
}

EIGEN_DECLARE_TEST(inplace_decomposition)
{
	EIGEN_UNUSED typedef Matrix<double, 4, 3> Matrix43d;
	for (int i = 0; i < g_repeat; i++) {
		CALL_SUBTEST_1((inplace<LLT<Ref<MatrixXd>>, MatrixXd>(true, true)));
		CALL_SUBTEST_1((inplace<LLT<Ref<Matrix4d>>, Matrix4d>(true, true)));

		CALL_SUBTEST_2((inplace<LDLT<Ref<MatrixXd>>, MatrixXd>(true, true)));
		CALL_SUBTEST_2((inplace<LDLT<Ref<Matrix4d>>, Matrix4d>(true, true)));

		CALL_SUBTEST_3((inplace<PartialPivLU<Ref<MatrixXd>>, MatrixXd>(true, false)));
		CALL_SUBTEST_3((inplace<PartialPivLU<Ref<Matrix4d>>, Matrix4d>(true, false)));

		CALL_SUBTEST_4((inplace<FullPivLU<Ref<MatrixXd>>, MatrixXd>(true, false)));
		CALL_SUBTEST_4((inplace<FullPivLU<Ref<Matrix4d>>, Matrix4d>(true, false)));

		CALL_SUBTEST_5((inplace<HouseholderQR<Ref<MatrixXd>>, MatrixXd>(false, false)));
		CALL_SUBTEST_5((inplace<HouseholderQR<Ref<Matrix43d>>, Matrix43d>(false, false)));

		CALL_SUBTEST_6((inplace<ColPivHouseholderQR<Ref<MatrixXd>>, MatrixXd>(false, false)));
		CALL_SUBTEST_6((inplace<ColPivHouseholderQR<Ref<Matrix43d>>, Matrix43d>(false, false)));

		CALL_SUBTEST_7((inplace<FullPivHouseholderQR<Ref<MatrixXd>>, MatrixXd>(false, false)));
		CALL_SUBTEST_7((inplace<FullPivHouseholderQR<Ref<Matrix43d>>, Matrix43d>(false, false)));

		CALL_SUBTEST_8((inplace<CompleteOrthogonalDecomposition<Ref<MatrixXd>>, MatrixXd>(false, false)));
		CALL_SUBTEST_8((inplace<CompleteOrthogonalDecomposition<Ref<Matrix43d>>, Matrix43d>(false, false)));
	}
}
